Ventricular conduction delay trending system and method

• US 20020062139A1
• Filed: 01/22/2002
• Published: 05/23/2002
• Est. Priority Date: 07/13/2000
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Ding, Jiang
• Granted Patent: US 6,763,267 B2
• Time in Patent Office: Days
• US Class Current: 607/25
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

A method and system for ascertaining the condition of the heart'"'"'s conduction system in a patient treated for congestive heart failure with pacing therapy. In accordance with the invention, changes in ventricular activation patterns are monitored over time in order to detect changes in the heart'"'"'s conduction system that may occur due to physiological regeneration of conduction pathways. The activation patterns are reflected by electrogram signals detected from different ventricular locations. By measuring the difference in conduction times of an excitation impulse traveling from the AV node to the different ventricular locations, a parameter representative of the heart'"'"'s conduction system is obtained that may be used to adjust the pacing therapy in accordance therewith.

Claims

1. A method for operating a cardiac pacemaker, comprising:

sensing electrical events occurring at an atrial location through an atrial sensing channel and at first and second ventricular locations through first and second ventricular sensing channels;

detecting a P wave from the atrial sensing channel;

detecting first and second R-waves from the first and second ventricular sensing channels;

measuring first and second PR intervals for the detected first and second R-waves; and

,

calculating a conduction delay as the difference between the first and second PR intervals.

2. The method of claim 1 further comprising determining if an atrial pace has been delivered and regarding the time of occurrence of the pace as a P wave.

3. The method of claim 1 further comprising calculating and storing conduction delays on a periodic basis.

4. The method of claim 1 further comprising calculating and storing conduction delays upon a command received from an external programmer.

5. The method of claim 4 further comprising stopping pacing before calculation of a conduction delay upon a command received from an external programmer.

6. The method of claim 1 further comprising providing a warning if a conduction delay exceeds or falls below a specified limit value.

7. The method of claim 1 further comprising calculating a trend based upon past measurements of conduction delays.

8. The method of claim 1 further comprising providing a warning upon a sudden change in the calculated conduction delay.

9. The method of claim 1 further comprising calculating conduction delays with respect to a third ventricular location.

10. The method of claim 1 further comprising adjusting pacing parameters based upon calculated conduction delays over a period of time.

11. The method of claim 10 wherein the AV interval of the pacemaker is decreased or increased in accordance with an increase or decrease, respectively, of an average of conduction delays measured over a period of time.

12. The method of claim 1 further comprising transmitting data from the pacemaker to an external programmer and displaying trended conduction delays between selected regions.

13. The method of claim 1 further comprising transmitting data from the pacemaker to an external programmer and displaying conduction delays in the form of means and standard deviations over the last period of data collection.

14. The method of claim 1 further comprising transmitting data from the pacemaker to an external programmer and displaying slopes of changes in conduction delays over a last data collection period.

15. The method of claim 1 further comprising transmitting data from the pacemaker to an external programmer and displaying a notification if a conduction delay increases or decreases to a predetermined limit value.

16. A storage medium containing processor-executable code for performing the method recited in claim 1.

18. The pacemaker of claim 17 further comprising logic circuitry for automatically measuring conduction delay values on a periodic basis and storing the values in memory.

19. The pacemaker of claim 17 further comprising an atrial pacing channel and wherein logic circuitry detects delivery of an atrial pace and regards the time of occurrence of the pace as a P wave for purposes of measuring PR intervals.

20. The pacemaker of claim 17 further comprising logic circuitry for stopping pacing and calculating a conduction delay value upon receipt of a command from an external programmer through a telemetry interface.

21. The pacemaker of claim 17 further comprising a controller programmed to adjust pacing parameters based upon calculated conduction delays over a period of time.

22. The pacemaker of claim 17 further comprising a third ventricular sensing channel for sensing depolarizations at a third ventricular location and logic circuitry for measuring a PR interval and calculating conduction delay values with respect thereto.

24. The pacemaker of claim 23 further comprising circuitry for automatically measuring conduction delay values on a periodic basis and storing the values in memory.

25. The pacemaker of claim 23 further comprising an atrial pacing channel and wherein the detection circuitry waits for an intrinsic P wave for measurement of PR intervals.

26. The pacemaker of claim 25 wherein the controller is programmed to turn pacing off before measurement of PR intervals and calculation of conduction delays.

27. The pacemaker of claim 23 further comprising an atrial pacing channel and wherein the detection circuitry detects delivery of an atrial pace and regards the time of occurrence of the pace as a P wave for purposes of measuring PR intervals.

28. The pacemaker of claim 25 wherein the controller is programmed to measure PR intervals during atrial pacing

29. The pacemaker of claim 23 further comprising a third ventricular sensing channel for sensing depolarizations at a third ventricular location and circuitry for measuring a PR interval and calculating conduction delay values with respect thereto.

30. The pacemaker of claim 23 wherein the controller is programmed to calculate and store conduction delays upon a command received from an external programmer.

31. The pacemaker of claim 28 wherein the controller is programmed to stop pacing before calculation of a conduction delay upon a command received from an external programmer.

32. The pacemaker of claim 23 wherein the controller is programmed to provide a warning if a conduction delay exceeds or falls below a specified limit value.

33. The pacemaker of claim 23 wherein the controller is programmed to provide a warning upon a sudden change in the calculated conduction delay.

34. The pacemaker of claim 23 wherein the controller is programmed to calculate a trend based upon past measurements of conduction delays.

35. The pacemaker of claim 23 wherein the controller is programmed to calculate conduction delays in the form of means and standard deviations over the last period of data collection.

36. The pacemaker of claim 23 wherein the controller is programmed to calculate a slope of changes in the conduction delays over the last data collection period.

37. The pacemaker of claim 23 wherein the controller is programmed to calculate a prediction of future conduction delay values based upon past history.

38. The pacemaker of claim 23 further comprising a second ventricular pacing channel and wherein the controller is programmed to deliver paces through the first and second pacing channels to two ventricular sites after the programmed AV interval following an atrial sense or pace.

39. The pacemaker of claim 38 further comprising an atrial pacing channel and wherein the detection circuitry waits for an intrinsic P wave for measurement of PR intervals.

40. The pacemaker of claim 39 wherein the controller is programmed to turn pacing off before measurement of PR intervals and calculation of conduction delays.

41. The pacemaker of claim 38 further comprising an atrial pacing channel and wherein the detection circuitry detects delivery of an atrial pace and regards the time of occurrence of the pace as a P wave for purposes of measuring PR intervals.

42. The pacemaker of claim 41 wherein the controller is programmed to measure PR intervals during atrial pacing.

17. A cardiac pacemaker, comprising;

an atrial sensing channel for sensing electrical events occurring in an atrium;

first and second ventricular sensing channels for sensing electrical events occurring at first and second ventricular locations;

a ventricular pacing channel and associated logic circuitry for pacing a ventricle in response to sensed events and lapsed time intervals;

logic circuitry for detecting R waves in the ventricular sensing channels following detection of a P wave due to a detected atrial depolarization; and

,

logic circuitry for measuring first and second PR intervals associated with the first and second ventricular sensing channels, and calculating a conduction delay value as the difference between the first and second PR intervals.

23. A cardiac pacemaker, comprising;

an atrial sensing channel for sensing electrical events occurring in an atrium;

first and second ventricular sensing channels for sensing electrical events occurring at first and second ventricular locations;

a ventricular pacing channel and a controller for pacing a ventricle in response to sensed events and lapsed time intervals in a mode such that the ventricle is paced at a programmed AV interval after an atrial sense or pace;

circuitry for detecting R waves in the ventricular sensing channels following detection of a P wave due to a detected atrial depolarization;

circuitry for measuring first and second PR intervals associated with the first and second ventricular sensing channels, and calculating a conduction delay value as the difference between the first and second PR intervals; and

,

wherein the controller is programmed to decrease or increase the programmed AV interval in accordance with an increase or decrease, respectively, of an average of conduction delays measured over a period of time.